The actor believes it is important to acquaint himself with the horrors being perpetrated around the world, however difficult it might be to watch.

He disagrees with the notion that violent films – including his new film, The Gunman – have anaesthetised audiences to real violence.

Asked if he watched Isil videos out of a sense of moral responsibility, Penn replied: “Uh-huh. I’ve watched them.

“And anyone who sees them and claims that they were anaesthetised by violent movies, that they weren’t horrified by what they saw, on the most primal level, is intellectually dishonest or existentially unpresent.”

Speaking to The Telegraph, Penn said: “The problem is we are not seeing enough of real violence. We are being anaesthetised when you don’t see the horror of war.

“In the Sixties, we grew up with the horror of Vietnam on our television screens every day. Today we have become anaesthetised by political correctness. The American news channels did this with the Iraq war; they wouldn’t show what it was about, they wouldn’t show the caskets coming home.”